This invention relates to a membrane useful for separating carbon dioxide from a carbon dioxide-containing gas mixture and to a method of preparing such a membrane. The present invention is also directed to a carbon dioxide carrier composition useful for the formation of such a membrane.
One known method for the separation of carbon dioxide from a carbon dioxide-containing gas mixture uses a liquid film across which carbon dioxide is selectively transported. The liquid film contains dissolved therein a carrier substance, typically an alkali metal carbonate (Science, 115, 44(1967); Science, 156, 1481(1967)). While the known liquid film has relatively good carbon dioxide selectivity and carbon dioxide permeability, the separation efficiency thereof is not fully satisfactory in actual, large scale utilization. In particular, the known liquid film poses a problem of leakage or drying up of the carrier liquid during use.